Dietary fat has been linked to breast cancer mortality by both epidemiological and animal studies. The proposed trial aims to study the effects of a low-fat (20%) diet on rates of recurrence and survival in women with Stage II breast cancer. The major concerns in developing the protocol include (1) controlling for known risk factors; (2) gaining and monitoring compliance to the proposed diet by the study group; and (3) avoiding adoption of the proposed diet by the control group. The physiological effects of the low-fat diet will be assessed to determine which subgroups of these Stage II breast cancer patients might gain improved health/prognosis by adherence to a low fat diet. The effects of the diet on serum cholesterol levels and body anthropometrics will be investigated as the variables which might play a key role in improving prognosis for this specialized group of patients. In addition, we hope to assess the ability of this specific patient population to adhere to a low fat diet. The effectiveness of the techniques used to gain and monitor subject compliance will be evaluated. In this respect, patient motivation and instruction in the study diet as well as nutritional record-keeping techniques will be key elements in the study design. If improved subject prognosis and/or compliance are achieved, the diet and/or the techniques used to achieve compliance could be implemented to better existing nutrition therapy for breast cancer patients. The existence of both a Diet, Nutrition, and Cancer Training Program and the CCOP Community Oncology Program facilitates implementation of this program in this institution.